715 New Planets Discovered by NASA Outside Earth's Solar System

NASA announced Wednesday that 715 new planets have been discovered, increasing the current 1,000 known planets by about 75 percent.

The Kepler Mission, which launched in 2009 with the goal of discovering potentially habitable planets like Earth, revealed the new planets that orbit 305 stars in systems much like Earth’s solar system, a NASA release said.

“Nearly 95 percent of these planets are smaller than Neptune, which is almost four times the size of Earth,” the release said. “This discovery marks a significant increase in the number of known small-sized planets more akin to Earth than previously identified exoplanets, which are planets outside our solar system.”

The first planets outside Earth’s solar system were discovered about 20 years ago, and identifying new planets has been what NASA called a “laborious planet-by-planet process.” But this new batch of planets came about after using a new statistical technique that allows scientists to consider many planets at once if they’re in a system that has more than one planet around the same star, the NASA release said.

The technique is called “verification by multiplicity” and uses the logic of probability to determine stars that are multiple-planet candidates.

NASA said four of the planets are less than 2.5 times the size of Earth and orbit in their sun’s habitable zone.

Kepler has found more than 3,600 planet candidates since its launch, and 961 have been verified as “bona-fide worlds,” NASA said.